The present invention relates to a stacker device used in, for example, a sheet feed type image reading apparatus or the like, and more particularly to a stacker device provided with a lifting member for raising or lowering a tray.
In a sheet feed type image reading apparatus, a hopper unit for stacking and accommodating paper or the like which is subject to reading and a stacker unit in which the paper or the like for which reading has been completed is stacked are generally disposed separately. A read head for reading characters, images, and the like on the paper or the like is disposed midway in a transport passage from the hopper unit to the stacker unit.
There is a type of a stacker unit which includes a stacker in which the paper or the like for which reading has been completed properly is stacked and a reject stacker in which the paper or the like for which reading has not been completed properly is stacked. The paper or the like which has been read by the read head is sorted into the respective stackers depending on the result of reading.
For example, in a related stacker device, in order to ensure that the discharged sheets can be stacked orderly without being arranged haphazardly, the discharged sheets are consecutively transported to a tray, and when the sheets have been stacked by a fixed quantity, the tray is lowered. (Refer to, for example, JP-A-11-165937.)
In addition, in a related device which has a rejecting function for a case in which a fault has occurred in reading, recognition, and the like, a structure is adopted in which a paper transporting passage separate from a normal transport passage is generally provided for rejection to discharge the rejected sheet onto a separate tray. (Refer to, for example, JP-A-08-081108.)
As described above, the following problems are encountered in the related art.
The capacities of the hopper and the stacker have come to increase in conjunction with improvement in the processing performance. With the related art, if the stacking depth becomes deep, since the stiffness is low particularly in the case of thin paper, there is a problem in that the leading end droops down, so that the paper drops in a curled state, and the stacking characteristic becomes very poor.
In addition, optimal stacking conditions vary depending on thin paper with weak stiffness, thick paper, and large- or small-sized paper. However since no consideration is given to the stacking positions corresponding to the types of paper, there is a problem in that paper with a poor stacking characteristic is generated.
Since there are many cases where the discharged paper tray is provided on an upper side of the device in conjunction with the trend toward a large-sized device, and an extension is extended to stack a large-sized medium, there is a problem in that the paper is very difficult to remove.
In the device which has the rejecting function for a case in which a fault has occurred in reading, recognition, and the like, the structure is adopted in which a paper transporting passage separate from a normal transport passage is generally provided for rejection to discharge the rejected sheet onto a separate tray. However, since the separate transporting passage is provided, there is a problem in that the device becomes large in size.